At present, many types of input devices are applicable in a computer system for performing operations, for example, mouse, button, touch screen, joystick, and the like. Due to the ease of use, the versatility in operation, the ever-decreasing price and the steadily improving yield, the touch screen is becoming more and more popular. As the touch screen gradually comes into people's lives, the past input devices are gradually eliminated from people's vision. Touch screens may be classified into an out-cell type and an embedded type. For an out-cell type touch screen, a panel having touch control function is arranged in front of the display device, and the touch surface covers the visual area of the display area. An embedded type touch screen is to integrate the touch control function into the panel of the display device, to the outside of which protective glass may be attached or not. The user can carry out the touch control operation by touching the screen with a finger. The embedded type touch screen may be further classified into two types: in cell and on cell. An on-cell type touch screen makes a touch sensing element (touch electrode) on the outside of the display screen, to which other elements such as a polarizer and protective glass are attached. For an in-cell type touch screen, the touch sensing element is typically fabricated on the glass substrate side of the array substrate, and then a complete display panel is made to achieve the touch control function.
A conventional touch sensing element is designed as comprising a plurality of touch electrodes in the horizontal direction and a plurality of touch electrodes in the vertical direction to form electrode patterns that intersect each other. However, for an in-cell type touch screen, if it is designed in this manner, the touch control is inevitably disturbed by the data lines or gate lines in pixels of the display panel, which may thereby result in a false touch point.
Another conventional touch sensing element is designed as multiplexing a common electrode as a touch sensing element by time-division multiplexing. FIG. 1 illustrates a pattern of a common electrode in the prior art which is multiplexed as a touch sensing element. As shown in FIG. 1, the common electrode is divided into a plurality of electrode blocks which are discontinuous in both the horizontal direction and the vertical direction. A plurality of touch signal lines and each electrode block of the common electrode are arranged in different layers at a position corresponding to each electrode block, and the touch signal lines can be electrically connected to corresponding electrode blocks through via holes. The touch signal line is further connected to a touch detection chip (not shown in FIG. 1) to provide a touch signal (driving signal) to respective electrode blocks. These touch signal lines are usually formed of a metal material, and therefore these touch signal lines can be referred to herein as touch pattern metals (TPM). However, a disadvantage of setting these touch signal lines is that they may affect the aperture ratio of pixels of the display device, thereby affecting the image quality and the visual effect for the final display product. Furthermore, the formation of touch pattern metals (TPM) brings about additional materials and processes to the display device during the actual manufacturing process, resulting in an increase in the cost of the display device.